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IO::Capture::Stdout(3)User Contributed Perl DocumentatioIO::Capture::Stdout(3)

       IO::Capture::Stdout - Capture any output	sent to	STDOUT

	   # Generic example (Just to give the overall view)
	   use IO::Capture::Stdout;

	   $capture = IO::Capture::Stdout->new();

	   $capture->start();	       # STDOUT	Output captured
	   print STDOUT	"Test Line One\n";
	   print STDOUT	"Test Line Two\n";
	   print STDOUT	"Test Line Three\n";
	   $capture->stop();	       # STDOUT	output sent to wherever	it was before 'start'

	   # In	'scalar	context' returns next line
	   $line = $capture->read;
	   print "$line";	  # prints "Test Line One"

	   $line = $capture->read;
	   print "$line";	  # prints "Test Line Two"

	   # move line pointer to line 1

	   $line = $capture->read;
	   print "$line";	  # prints "Test Line One"

	   # Find out current line number
	   $current_line_position = $capture->line_pointer;

	   # In	'List Context' return an array(list)
	   @all_lines =	$capture->read;

	   # More useful example 1 - "Using in module tests"
	   #  Note: If you don't want to make users install
	   #	    the	IO::Capture module just	for your tests,
	   #	    you	can just install in the	t/lib directory
	   #	    of your module and use the lib pragma in
	   #	    your tests.

	   use lib "t/lib";
	   use IO::Capture::Stdout;

	   use Test::More;

	   my $capture =  IO::Capture::Stdout->new;

	   # execute with a bad	parameter to make sure get
	   # an	error.

	   ok( ! $test("Bad Parameter")	);


       The module "IO::Capture::Stdout", is derived from the abstract class
       "IO::Capture".  See IO::Capture.	The purpose of the module (as the name
       suggests) is to capture any output sent to "STDOUT".  After the capture
       is stopped, the STDOUT filehandle will be reset to the previous
       location. E.g., If previously redirected	to a file, when
       "IO::Capture->stop" is called, output will start	going into that	file

       Note:  This module won't	work with the perl function, system(), or any
       other operation
	      involving	a fork().  If you want to capture the output from a
       system command,
	      it is faster to use open() or back-ticks.

	      my $output = `/usr/sbin/ls -l 2>&1`;

       o   Creates a new capture object.

       o   An object can be reused as needed, so will only need	to do one of

	   o   Be aware, any data previously captured will be discarded	if a
	       new capture session is started.

       o   Start capturing data	into the "IO::Capture" Object.

       o   Can not be called on	an object that is already capturing.

       o   Can not be called while STDOUT tied to an object.

       o   "undef" will	be returned on an error.

       o   Stop	capturing data and point STDOUT	back to	it's previous output
	   location I.e., untie	STDOUT

       o   In Scalar Context

	   o   Lines are read from the buffer at the position of the
	       "line_pointer", and the pointer is incremented by one.

		   $next_line =	$capture->read;

       o   In List Context

	   o   The array is returned.  The "line_pointer" is not affected.

		   @buffer = $capture->read;

       o   Data	lines are returned exactly as they were	captured.  You may
	   want	to use "chomp" on them if you don't want the end of line

	       while (my $line = $capture->read) {
		   chomp $line;
		   $cat_line = join '',	$cat_line, $line;

       o   Reads or sets the "line_pointer".

	       my $current_line	= $capture->line_pointer;

   Adding Features
       If you would like to sub-class this module to add a feature (method) or
       two, here is a couple of	easy steps. Also see IO::Capture::Overview.

       1.  Give	your package a name

	       package MyPackage;

       2.  Use this "IO::Capture::Stdout" as your base class like this:

	       package MyPackage;

	       use base	qw/IO::Capture::Stdout/;

       3.  Add your new	method like this

	       package MyPackage;

	       use base	qw/IO::Capture::Stdout/;

	       sub grep	{
		   my $self = shift;

		   for $line (

See Also



       Mark Reynolds

       Jon Morgan

       Copyright (c) 2003, Mark	Reynolds. All Rights Reserved.	This module is
       free software. It may be	used, redistributed and/or modified under the
       same terms as Perl itself.

perl v5.32.1			  2005-04-29		IO::Capture::Stdout(3)


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